Electric welding appliance



July 19 1927.

J. WQWILKINSON ELECTRIC WELDING APPLIANCE Filed' May 4' 1925 Jive/7102',

Patented July 19, 1927.

UNITED STATES.

JAM 38W. WILKINSON, OF KANSAS CITY, KANSAS.

ELECTRIC WELDING APPLIANCE.

Application filed May 4,

This invention relates to electric welding apparatus and has for one of its objects to produce a pair of coils, comprising an inductive resistance, said coils being so arranged in series in an alternating current circuit as to be variable to produce any desired reactance for welding purposes, and each of the lead lines from the source of alternating current energy being connected to oneof said coils so that upon change inthe direction of the current, it will pass through a coil before attaining the work or electrode respectively. By this means, that is passing the current through a resistance before it reaches the work, the voltage is lowered regardle'ss of the direction of flow of the current and splashing is avoided due to the fact that the voltage is under steady control for the production of an even arc.

Another object is to roduce means operated by the ma netic e ect of the reactor for the agitation o a cooling medium surroundng the coils. A still further object is to produce automatic means for the interruption of the welding circuit upon the breaking or inter-' ruption of an auxiliary or shunt signal circult.

A still further object is to produce a strong, durable and efiicient apparatus of. the character mentioned, and in order that it may be fully understood, reference is to be had to the accompanying drawing, in which: I

Figure 1 is a side elevation of a reactor embodying the invention .and equipped with fluid agitators.

Figure 2 is a section on the line IIII of Figure 1.

Figure 3 is a section taken through the reactance coils to show the method of winding.

Figure 4 is a diagrammatic view of the circuit and also illustrates the method of. winding the reactor.

In the said drawing, where like reference characters identify corresponding parts in all of the figures, 1 indicates a circular base of an suitable insulating material and forme with a central opening within which is secured a vertical tube 2 of rather light metal and in practice forming the core of an electro-magnet, as will hereinafter appear.

The base 1 is formed with a series of openings arranged radially, within which open ings cylindrical insulating spacer rods 3 are 1925. Serial No. 27,762.

secured. The device comprises a pair of separate mutually inductive coils whose operation is hereinbelow set forth in detail. The inside coil 4 is spaced from the tube 2 by a series of the rods 3, and said coil is composed of two superimposed windings, spaced apart by a series of rods 3, itbeing understood, of course, that each winding is com pleted and then the outside rods 3 for such Winding are inserted in position.

After the winding of the inner coil 4, the outer coil 5, composed of three windings is placed in position, and is wound in the opposite direction from the coil 4:, the first coil of said winding 5 being spaced from the last'coil of the inner winding by a series of the spacer rods 3, and each succeedin winding is likewise spaced from its nelghbors by similar rods. It is to be understood 5 that the windings are spaced apart by the rods 3, for the more efiicient cooling of the reactor.

' the inner winding of'the outer coil. The extremity of the inner winding of the inner coil is then connected by a wire 9 to the work W, and the extremity of the outer winding of the outer coil is connected by a wire 10 to a switch point 11. A switch 12, for electrical contact with such point, is connected by a wire 13 to the welding terminal or torch 14. The switch may be closed on the point 11 or on any one of a series of similar points,- indicated at 15 and 16, connected to the outer coil at different points along its length. The lowest heat is generated when the switch is on int 11, the heat enerated increasing as t e switch is moved progressively to the points 15 and 16.- 7

The electrical cooperation between. the coils is substantially, as follows:-With an inductance inserted in series,'as in the present case, in an alternating current circuit at c ns a t supply voltage, the current pro- 'duced is approximately constant as long as the resistance of the circuit is small compared with the series inductive reactance. Therefore, with an increasing load, or in creasing resistance of the receiving circuit, the series inductive reactance has to be decreased, so as to maintain the total impedance of the circuit, and thereby the current, constant. In most constant current a paratus, as transformers, this variation 0 the series inductive reactance with the load is usually accomplished automatically by mechanical, motion. With the split inductance as shown in this application, the above conditions for constant current are obtained by variation of the self-inductive reactance through the proper proportioning of the number of turns on the inside coil to those on the outside coil, the diameter of the iron core, the len th of the core, and the relative spacing of 51a coils to one another, which allows for a variation of the leakage flux of the inductance. The variation of the leakage fiux at loads within the working range of the welding arc is primarily controlled by the degree of saturation of the iron by the leakage of magnetism. Any increase of current, as for instance, caused by touching the weldin material against the material to be wel ed, increases the magnetism produced, thereby increasing the counterelectromotive force and thus reducing the current flow. As the arc is struck the resistance within the arc is increased and a momentary reduction ,of the current is noted, but with a reduction of the counter-electromotive force which allows the su ply voltage to again increase the current dbw to the arc. As the distance between the electrodes is chan ed by the movement of the erson doing t e weldin the resistance within the are changes whic in turn causes a change in the current within the inductance, this change within the inductance causing the impedance to change in such a way as to bring about an almost constant current. The coeflicient of induction, according to theory at least, is constant for a constant frequency, but practical application of this specially constructed inductance with an open core, together with the changing permeability of the iron within the core due to the different degrees of saturation on account of leaka e,

gives the correct change of impedance wit 1n the electric circuit necessary to the production of the constant current which is desirable for good welding. Also, the opencore type of inductance allows a quick decay of the flux, thereby generating the necessary static spark for startin the are at the beginning of each alternation by its passing t rou h the residual hot vapor of the preceding half wave. I

In order to rovide means for visually indicating whether the welding circuit is alive and in proper working condition and also to provide means for the automatic interruption of the welding circuit in case there is a break in the signal circuit, due to the blowing of the signal (in this case a lamp) by an extreme increase in the voltage of the feed lines, the wire 10 of the outer coil is connected to a wire 17 shuntin the welding apparatus and work (see F1 re 4). A lamp and inductance coil 18 an 19 respectively are inserted in the length of said wire, it being a parent that as long as there is a current owing through the system, the lamp will glow and the coil will be energized.

The coil 19 is equipped with a s rin -actuated armature 20 for making and rea ing a circuit through the points 21 and 22 in the wire 9 connected to the work. Upon the interruption of the current through the signal circuit, the spring 23 of the armature 20 will break the circuit at points 21 and 22 and interrupt the welding clrcuit, as will be readily understood.

It has been found desirable to provide agitating means for the cooling medium surroun ding the reactor, and in order to effect such agitation without a separate source of power, a pair of bearing brackets 24 are secured to t e upper face of the top cap 6,'and pivotally mounted in said brackets and extending transversely of the reactor is a cross shaft 25 having a crank arm portion 26 centrally of its length equipped with a metallic plate 27 constituting an armature and being alternately attracted and repulsed by the core 2 of the reactor, thus producing an oscillation of the transverse shaft 25. The ends of the shaft are down-turned and are equipped with fan blades 28 for agitation of the cooling fluid. To prevent the repulsion of the armature 27 beyond .a predetermined distance a right-angle shaped stop 29 is attached to the cap 6 and overlies the armature as shown in Figures 1 and 2.

From the above descri tion, it will be apparent that I have prodhced a device of the character described which possesses all of the features of advantage set forth as desirable; and while I have described and claimed the preferred embodiment of the same, I reserve the ri ht to make all changes properly falling witfiin the spirit and scope of the appended claims.

I claim: I

1. In a reactor, a plurality of insulated coils wound in succession on the same core, a transverse shaft mounted on the up er end of said reactor and having a centre crank shaft, an armature plate attached to said crank shaft and adapted to be attracted and repulsed b the core, and agitators carried.

by the en of said shaft for agitating the cooling media surrounding the reactor. 2. A reactor comprising a core, a base and 1,836,266 1/ v r B.

a cap piece carried by said core, said base and cap pieces being formed witha series of concentrically arranged spacer rods extending from the base to the cap piece and carried thereby, a coil wound in one direction around a plurality of said concentrically arranged rods, and a second coil wound rods.

In witness whereof I hereunto aflix my signature.

/ JAMES W. WILKINSON. 

